Website design By BotEap.comOne of the most common codes I typically see on a 1997-2001 Toyota 2.2L Camry 4-Cylinder is a P0401. It is a code that indicates that there is a problem with the EGR system, not necessarily a problem with the EGR valve itself. I hear stories of people getting this code and replacing the EGR valve without doing any testing because they don’t know what to test. They spend unnecessary money and still haven’t fixed the problem.

Website design By BotEap.comThere are three parts that will usually cause this code to appear on your car. Yes, the EGR valve is one of them, but you also have the EGR VSV and the EGR modulator. The first parts of the inspection will be to check the operation of the EGR valve by applying a vacuum with a vacuum pump. You can get a vacuum pump at an auto parts store for around $20 and even rent one at some stores.

Website design By BotEap.comConnect the pump to the single vacuum port on your EGR valve. There will be a small hose attached, which you will need to disconnect and install your pump in the same port. With the engine idling, you should be able to pump the vacuum pump to create vacuum at the EGR valve. The diaphragm inside the EGR valve should rise up and kill the car. If your car dies, then your EGR valve and ports are fine. If your car stumbles or doesn’t have any change in the way it runs when it’s inhaling, you probably have a bad EGR valve or a clogged port on your intake.

Website design By BotEap.comIf you think you have a bad valve, you should remove it from the engine and test it with the same vacuum pump. You should be able to see the diaphragm move inside the valve as you apply the vacuum. If the diaphragm moves, you may have clogged intake ports and the intake may need to be cleaned. If it doesn’t move, you need to replace the EGR valve.

Website design By BotEap.comHowever, if your Camry stopped working when you applied that first vacuum, then you need to start looking for the EGR VSV. I know VS what? It’s a small blue solenoid located at the rear of the engine block. It will have a couple of vacuum hoses and a small plug attached to it, all held in there with a 10mm bolt. Remove the VSV and test it by applying power and ground from your car battery (the VSV should not be connected to the harness during testing). If you hear a click from the VSV when you apply power, then you need to replace the EGR Modulator.

Website design By BotEap.comThe EGR modulator is located to the right of the EGR valve on the intake. It will have several vacuum hoses coming out and it slides into a holder. The EGR modulator can be purchased relatively cheaply from your dealer. There are no easy tests for the modulator. If you replace the modulator and still have a problem and the light comes back on, you need to replace the EGR VSV, also known as a vacuum switching valve. Sometimes the VSV may have an internal break and still click when you turn on and ground the terminals, but it may still be bad.

Website design By BotEap.comSo you could be wasting your money just throwing in a valve. Remember that the only way to fix something right is to know the proper testing procedure so that you can arrive at a correct solution.